LXR qemu/ui/vnc-enc-zlib.c

   1/*
   2 * QEMU VNC display driver: zlib encoding
   3 *
   4 * Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>
   5 * Copyright (C) 2006 Fabrice Bellard
   6 * Copyright (C) 2009 Red Hat, Inc
   7 *
   8 * Permission is hereby granted, free of charge, to any person obtaining a copy
   9 * of this software and associated documentation files (the "Software"), to deal
  10 * in the Software without restriction, including without limitation the rights
  11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12 * copies of the Software, and to permit persons to whom the Software is
  13 * furnished to do so, subject to the following conditions:
  14 *
  15 * The above copyright notice and this permission notice shall be included in
  16 * all copies or substantial portions of the Software.
  17 *
  18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24 * THE SOFTWARE.
  25 */
  26
  27#include "qemu/osdep.h"
  28#include "vnc.h"
  29
  30#define ZALLOC_ALIGNMENT 16
  31
  32void *vnc_zlib_zalloc(void *x, unsigned items, unsigned size)
  33{
  34    void *p;
  35
  36    size *= items;
  37    size = (size + ZALLOC_ALIGNMENT - 1) & ~(ZALLOC_ALIGNMENT - 1);
  38
  39    p = g_malloc0(size);
  40
  41    return (p);
  42}
  43
  44void vnc_zlib_zfree(void *x, void *addr)
  45{
  46    g_free(addr);
  47}
  48
  49static void vnc_zlib_start(VncState *vs)
  50{
  51    buffer_reset(&vs->zlib.zlib);
  52
  53    // make the output buffer be the zlib buffer, so we can compress it later
  54    vs->zlib.tmp = vs->output;
  55    vs->output = vs->zlib.zlib;
  56}
  57
  58static int vnc_zlib_stop(VncState *vs)
  59{
  60    z_streamp zstream = &vs->zlib.stream;
  61    int previous_out;
  62
  63    // switch back to normal output/zlib buffers
  64    vs->zlib.zlib = vs->output;
  65    vs->output = vs->zlib.tmp;
  66
  67    // compress the zlib buffer
  68
  69    // initialize the stream
  70    // XXX need one stream per session
  71    if (zstream->opaque != vs) {
  72        int err;
  73
  74        VNC_DEBUG("VNC: initializing zlib stream\n");
  75        VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);
  76        zstream->zalloc = vnc_zlib_zalloc;
  77        zstream->zfree = vnc_zlib_zfree;
  78
  79        err = deflateInit2(zstream, vs->tight->compression, Z_DEFLATED,
  80                           MAX_WBITS,
  81                           MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
  82
  83        if (err != Z_OK) {
  84            fprintf(stderr, "VNC: error initializing zlib\n");
  85            return -1;
  86        }
  87
  88        vs->zlib.level = vs->tight->compression;
  89        zstream->opaque = vs;
  90    }
  91
  92    if (vs->tight->compression != vs->zlib.level) {
  93        if (deflateParams(zstream, vs->tight->compression,
  94                          Z_DEFAULT_STRATEGY) != Z_OK) {
  95            return -1;
  96        }
  97        vs->zlib.level = vs->tight->compression;
  98    }
  99
 100    // reserve memory in output buffer
 101    buffer_reserve(&vs->output, vs->zlib.zlib.offset + 64);
 102
 103    // set pointers
 104    zstream->next_in = vs->zlib.zlib.buffer;
 105    zstream->avail_in = vs->zlib.zlib.offset;
 106    zstream->next_out = vs->output.buffer + vs->output.offset;
 107    zstream->avail_out = vs->output.capacity - vs->output.offset;
 108    previous_out = zstream->avail_out;
 109    zstream->data_type = Z_BINARY;
 110
 111    // start encoding
 112    if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {
 113        fprintf(stderr, "VNC: error during zlib compression\n");
 114        return -1;
 115    }
 116
 117    vs->output.offset = vs->output.capacity - zstream->avail_out;
 118    return previous_out - zstream->avail_out;
 119}
 120
 121int vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
 122{
 123    int old_offset, new_offset, bytes_written;
 124
 125    vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_ZLIB);
 126
 127    // remember where we put in the follow-up size
 128    old_offset = vs->output.offset;
 129    vnc_write_s32(vs, 0);
 130
 131    // compress the stream
 132    vnc_zlib_start(vs);
 133    vnc_raw_send_framebuffer_update(vs, x, y, w, h);
 134    bytes_written = vnc_zlib_stop(vs);
 135
 136    if (bytes_written == -1)
 137        return 0;
 138
 139    // hack in the size
 140    new_offset = vs->output.offset;
 141    vs->output.offset = old_offset;
 142    vnc_write_u32(vs, bytes_written);
 143    vs->output.offset = new_offset;
 144
 145    return 1;
 146}
 147
 148void vnc_zlib_clear(VncState *vs)
 149{
 150    if (vs->zlib.stream.opaque) {
 151        deflateEnd(&vs->zlib.stream);
 152    }
 153    buffer_free(&vs->zlib.zlib);
 154}
 155